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versión On-line ISSN 2078-5135versión impresa ISSN 0256-9574

SAMJ, S. Afr. med. j. vol.98 no.9 Cape Town sep. 2008

FORUM ISSUES IN PUBLIC HEALTH

Road traffic injury: Prioritising interventions

R MatzopoulosI; J E MyersII; R JobanputraIII

IRichard Matzopoulos is a specialist scientist at the Crime, Violence and Injury Lead Programme, and is affiliated to the Medical Research Council, the UNISA Institute for Social and Health Sciences, and the School of Public Health and Family Medicine of the University of Cape Town IIJonny Myers is Director of the Occupational and Environmental Health Research Unit, and Professor in the School of Public Health and Family Medicine of the University of Cape Town IIIRahul Jobanputra is a transport policy consultant and affiliated to the Centre for Transport Studies, University of Cape Town

Background

The Burden of Disease (BoD) Reduction Project1 of the Western Cape Department of Health reviewed the risk of traffic-related injury and best-practice interventions, for possible application in the province.2

According to global estimates, 1.2 million people are killed and 50 million are injured in road traffic crashes annually, with an anticipated increase of 65% over the next two decades unless there is determined commitment to prevention.3 Eighty-five per cent of road deaths occur in low- to middle-income countries (LMICs) where improved road safety has not been a sustainable concern.3 Road traffic crashes also damage property and infrastructure and adversely affect productivity as a result of transport disruption; the total cost is an estimated R42.5 billion in South Africa in 1998 alone.4

Injuries are the second-biggest contributor (one-fifth) to the provincial BoD after the major infectious diseases of HIV and TB (comprising 22%). The road traffic injury burden for the province is 6.9%, which is 40% higher than the national figure of 5%.5

Available provincial traffic injury data and the literature on related risks and interventions were reviewed; this included information on injury-related deaths in Cape Town and Stellenbosch from the National Injury Mortality Surveillance System (NIMSS),6 data generated by the surveillance working group of the Burden of Disease Reduction Project,7 the National Household Travel Survey,8 and the Arrive Alive website.9 Risks for road traffic injuries (RTIs) and associated interventions were mapped onto the biological, behavioural, societal and structural levels of the ecological approach employed by the BoD project.1 As injuries are predictable and preventable, while 'accidents' are random inevitable events, the term RTI (as adopted in the World Report on Road Traffic Injury Prevention3) is used throughout.

RTI risks

The focus of the BoD project is 'upstream' of RTI risks and related interventions (i.e. the more distant and structural determinants further up the causal chain) while downstream risks are closer to the injury outcome (e.g. single carriageways versus quality of emergency care). Upstream can also refer to interventions which are more remote from the risk being addressed (e.g. the legislating of speed governors in engines rather than the policing of speeding motorists). Upstream risks and interventions fall typically within the remit of sectors other than health (e.g. road design versus more rapid emergency response to crashes).

Biological risks for RTI include hearing, vision, attention, age (physical and emotional maturity, inexperience), illness and sex. Seventy-eight per cent of Cape Town traffic deaths were male.10 Risky driving exposes young people to hazardous situations which they are inexperienced in handling. Thirty-seven per cent of child traffic deaths occur on weekends when limited recreational facilities tend to cause children to contend more with fast-moving traffic and inebriated drivers. Pedestrians in the 5 - 9-year-old age group are particularly vulnerable when going to school11 as they lack the capacity to react appropriately.

Behavioural risks include substance abuse; aggressive driving (e.g. speeding, disobeying rules, taking chances); fatigue; distractions (e.g. cellphone use); and poor safety habits (e.g. non-use of seatbelts, child restraints and helmets). Cape Town mortality data highlight the alcohol-relatedness of deaths among both drivers (>55% of deaths) and pedestrians (>66%).11 Alcohol consumption increases the likelihood of crash occurrence, as well as the likelihood that death or serious injury will result. Crash risk begins to increase significantly at a blood alcohol concentration (BAC) of 0.04 g/dl, and rises exponentially thereafter.12-15 The South African BAC limit (0.05 g/dl) is exceeded by males <80 kg after 2 standard drinks (roughly equivalent to a beer, glass of wine or tot of spirits) and after 1 drink by women <55 kg.16 The limit for professional drivers is 0.02 g/dl. Aggressive behaviour is also a concern. Between 64% and 84% of KwaZulu-Natal drivers experienced aggressive driving (expressions of anger), while 18% were involved in arguments or an assault. Over half who drove when drunk said that they became more aggressive when intoxicated. Fifty-three per cent of drivers regularly exceeded speed limits, and 48% sped through yellow or red traffic lights.17 The probability of death associated with collisions increases exponentially with speed from about 10% at 30 km/h to more than 90% at 60 km/h.18

Societal risks include a culture of impunity (lawlessness and ineffective enforcement, particularly for minibus taxi and luxury vehicle drivers); irresponsible advertising that promotes speed; unsafe behaviour and unrealistic lifestyle choices where cars are valued as status symbols above more lasting assets such as houses; social pressure to speed (aggressive tailgating); and unsafe and unregulated vehicle design. While 2% of vehicles are not registered, an additional 3% are not tested for roadworthiness on transfer. Nationally, a total of R85 365 340 in fines was outstanding as at December 2005 while, typically, only 17% of fines issued are recovered (M Vanderschuren, personal communication, 19 November 2007).

Structural risks include multiple deprivation (e.g. poverty, residence far from employment and services); rapid urbanisation (increased pedestrian and small vehicle numbers); lack of transport infrastructure that separates pedestrians, non-motorised vehicles, motorised vehicles and mass transport; unsafe vehicles (e.g. vehicles that can exceed speed limits, bullbars, lights/indicators out of order); and road design (e.g. poor maintenance, drainage and illumination and absence of absorptive crash barriers, medians and multiple carriageways). Increasing night-time road lighting by 1 candela/m2 can reduce crashes by up to 65%.19 Inadequate public mass transport is a major risk for RTI. Nationally, 74% of households are dependent on public transport and walking.8 Local public transport relies on small motorised vehicles, which increase the probability of RTI, along with poor urban planning that provides limited crossing points, poor pedestrian access to amenities and non-separation from vehicular traffic. In Cape Town, which has the most developed commuter rail network, only 7.6% of commuters are served by rail, which is also subject to several safety concerns.20 Summary findings of the National Household Travel Survey are presented in Table I. Bus Rapid Transit, a cost-effective and environmentally friendly mass transit alternative, has been proposed and investigated for specific corridors, but has not received the necessary support.

Recommended interventions to reduce RTIs

The hierarchy of road safety interventions (as with safety in general) prioritises sustainable upstream structural interventions that substantially alter the urban and road environment, such as those that develop infrastructure for non-motorised and non-small-vehicle-based mass transport, rather than more downstream interventions targeting behaviour change in road users through, say, education campaigns. Apart from reducing RTIs and mitigating negative environmental effects of urbanisation, these strategies may also promote health if they lead to increased walking and cycling and cleaner air -provided the routes are accessible, convenient and safe. Urban transport infrastructure investment needs to be integrated with urban design and planning and community safety initiatives to ensure that networks are well utilised, highly visible and well policed, highlighting the critical need for effective inter-sectoral action integrating technical engineering and health care expertise.

While numerous interventions are possible for reducing the burden of RTI, the effectiveness of interventions in existing SA road safety strategies has not been established. A strong case can be made for implementing the few more downstream strategies aimed at road-users that have been shown to be effective across numerous settings, such as seatbelts, child restraints, helmet-wearing and the enforcement of speeding and driving-under-the-influence (DUI) legislation. Because the majority of fatally injured drivers exceed the legal BAC limit, the enforcement of DUI legislation should be the top priority intervention for local enforcement agencies and lawmakers, and should follow the implementation guidelines devised by international road safety agencies.16 Wearing safety belts, although compulsory, is neither strictly adhered to nor enforced in South Africa, especially for passengers. Helmet-wearing is well enforced and adhered to by motorcyclists, but not among cyclists, who are forced to use mixed-use public roads for at least part of their journey owing to lack of cycle path networks. Legislation and enforcement here would go hand-in-glove with non-motorised transport development policy.

A summary of risks and associated interventions that are feasible in the Western Cape is presented in Table II.

The need for an inter-sectoral approach

It is clear that implementation of these interventions will require effective inter-sectoral action involving government, the private sector, NGOs and the research community. Currently, structures that could support the requisite inter-sectoral action are poorly developed, which hinders comprehensive approaches to prevention that could effectively reduce RTIs.

For example, every effort is required to reduce vehicle speeds, which constitute a major determinant of crash incidence and severity, particularly in areas where fast-moving vehicles, pedestrians and cyclists share the road. Speed limits on urban arterial roads with encroaching informal settlements and areas with substantial pedestrian activity (schools and shops) should be regularly surveyed with a view to road engineering, enforcement or vehicle design solutions. In addition to more effective enforcement, successful interventions will require substantive changes to the socio-cultural landscape (driving behaviours), and restrictions on motor vehicle design and advertising (facilitating and glamourising fast, aggressive driving).

All interventions should be supported by an information system capable of monitoring and evaluating effectiveness and efficiency (costs and benefits). Evaluation should be conducted by an integrated multi-disciplinary team that is independent of implementing agencies, to ensure objectivity and best practice for safety promotion and injury prevention.

Equity aspects in planning and resource allocation are paramount in seeking protection for all road users, as those who do not possess motor vehicles currently bear a disproportionate share of road injury and risk.